This invention relates to filter press machines for separating solids from liquids, and more particularly to a novel, lightweight, more economical thermoplastic filter plate for use in such machines.
Thermoplastic filter plates of various type constructions have been utilized and suggested in the past. Typical prior constructions commonly made of polypropylene are shown in U.S. Pat. Nos. 4,229,304; 4,217,224; 4,166,035; 3,957,645; 3,931,014; and 3,926,811.
While some of these prior plates have been operatively acceptable in some applications, a need exists in the art for a plate which is cheaper and easier to manufacture and which consequently allows the selective use of various type thermoplastic materials possessing different temperature and chemical resistant characteristics within affordable cost limitations.
Accordingly, the primary object of this invention resides in the provision of a novel, lightweight thermoplastic filter plate which is relatively inexpensive and easy to manufacture, but yet possesses sufficient strength to withstand normal operating pressures of filter press machines.
Another object of the invention resides in the above filter plate which is constructed in two identical plate sections joined together in back to back relationship with the rearward faces of each section formed with a plurality of lattice type support ribs which butts against each other to form a hollow cellular type construction at least around the periphery of the plate.
Still another object of the invention resides in the provision of the above filter plate, wherein the plate sections may be advantageously foam molded to minimize the required molding time, and substantially reduce the finished weight of the plate, and therefor significantly reduce costs.
A further object of the invention resides in the provision of the above filter plate, wherein the plate sections may be more economically formed from various thermoplastic materials such as the commonly used polypropylene, or the more expensive plastics marketed under the tradenames Polysulfone, Kynar, or Ryton.
Other objects and advantages of the invention will become apparent by reference to the following detailed description of a preferred embodiment of the invention and to the accompanying drawings.